Showing papers by "University of Jena published in 1988"

The Boolean hierarchy I: structural properties

Abstract: In this paper, we study the complexity of sets formed by boolean operations (union, intersection, and complement) on NP sets. These are the sets accepted by trees of hardware with NP predicates as leaves, and together these form the boolean hierarchy.We present many results about the structure of the boolean hierarchy: separation and immunity results, natural complete languages, and structural asymmetries between complementary classes.We show that in some relativized worlds the boolean hierarchy is infinite, and that for every k there is a relativized world in which the boolean hierarchy extends exactly k levels. We prove natural languages, variations of VERTEX COVER, complete for the various levels of the boolean hierarchy. We show the following structural asymmetry: though no set in the boolean hierarchy is ${\text{D}}^{\text{P}} $-immune, there is a relativized world in which the boolean hierarchy contains ${\text{coD}}^{\text{P}} $-immune sets.Thus, this paper explores the structural properties of the...

Thioacetamide-induced cirrhosis-like liver lesions in rats--usefulness and reliability of this animal model.

Abstract: Summary Long term administration ofthioacetamide (0.03% in tap water) results in a characteristic lesion in rat liver, which corresponds to cirrhosis-like patterns of micronodular cirrhosis type after treatment over 3 months. During its development a reproducible temporal course of biochemical and morphological changes can be recognized. After withdrawal of the toxic agent this lesion persists for about 2 months. Then the cirrhosis-like alterations recede and a proliferation of bile ducts predominates, which is associated with increasing portal fibrosis altering the pattern and relatively enhancing the total collagen content of the liver. Considering these peculiarities, the TAA-model is suitable for investigations into connective tissue metabolism in the fibrotic liver and cirrhosis-like patterns. Search for and test of therapeutic principles should be done during TAA-administration (prophylactic agents) or within 2 months after withdrawal of toxic agents (therapeutics).

NMR determinations of SiOSi bond angle distributions in silica

Abstract: The 29 Si NMR chemical shift in crystalline silicates is strongly dependant on the SiOSi bond angle, hence, if a suitable relationship between shift and angle can be obtained then the shape of the NMR line in glasses can be used to give information about the statistical distribution of bond angles and by transformation the SiSi partial pair correlation function in these materials. Several functional relationships between shift and angle have been given in the literature and these result in different SiOSi bond angle distributions deduced. This paper will try to review the current situation and comment on the prospect of an NMR alternative to X-ray diffraction structural determinations.

Analytical treatment of band-gap underestimates in the local-density approximation.

Abstract: Corrections to band gaps calculated within the density-functional local-density approximation are obtained as self-energy differences, computed according to the GW approximation. Local-field and dynamical screening effects are neglected. The use of a model dielectric function and of simple tight-binding wave functions leads to an analytic formula for the gap correction valid for semiconductors and insulators crystallizing in the diamond and zinc-blende structures. The results obtained for many materials are in very good agreement with experiment.

Self-similar random measures

Abstract: A set is called self-similar if it is decomposable into parts which are similar to the whole. This notion was generalized to random sets. In the present paper an alternative, axiomatic approach is given which makes precise the following idea (using Palm distribution theory): A random set is statistically self-similar if it is statistically scale invariant with respect to any center chosen at random from that set. For these sets Hausdorff dimension coincides with an intrinsic self-similarity index.

Investigation of optical tunneling through nonlinear films

Abstract: The tunneling phenomenon of light waves that are totally reflected at one of the film interfaces will be considerably modified when the dielectric coefficient of the film becomes intensity dependent. We present an exact analytical approach that describes the tunneling of totally reflected, transverse-electric-polarized plane waves through a nonlinear film, the dielectric function of which may reveal material saturation. Within certain parameter ranges the configuration shows a pronounced switching between total internal reflection (off state) and the onset of complete transmission (on state). The switching characteristic can be tuned either by the angle of incidence or by the input intensity from monostable to bistable response. An experimental demonstration of the predicted results has been performed by using a liquid-crystal p-methoxybenzilidene-p-n-butylaniline film sandwiched between two optical prisms.

Theory of the influence of the second co-ordination sphere on the chemical shift

Abstract: Starting from a description of a molecular wave function using bond orbitals a general formula was derived describing the change of an expectation value of a one electron operator with bond polarization. This equation leads to a bond additive scheme for the description of bond polarization effects containing matrix elements of the Fock-operators. For these matrix elements simple formulae were derived for the case of a point charge approximation. In a second part of the paper this formalism is used for the interpretation of the influence of the second co-ordination sphere on the chemical shift. This scheme is used for a discussion of the 1H chemical shifts of selenites. The variation of the chemical shifts in dependence of the geometry of the hydrogen bond can be understood. Furthermore the theory proved to be useful for the interpretation of the bond angle dependence of 29Si chemical shifts in silica polymorphs. Finally it is possible to study π-bond polarization of various substituents and its influence ...

Evolution of nonlinear guided optical fields down a dielectric film with a nonlinear cladding

Abstract: We present a comprehensive, numerically oriented investigation of spatially nonstationary, TE-polarized optical field distributions guided by a thin film that can support both TE and TE waves. The film is asymmetrically bounded by a Kerr-like nonlinear cladding that may exhibit linear material losses. All field distributions have been generated by exciting different guided waves at one of the film end faces and tracing them down the film with the help of an extended propagating beam method. The long-distance asymptotic behavior is of particular interest. The numerical-stability analysis of the dispersion curve for nonlinear guided waves (NGW’s) indicates that the positively sloped TE0 branches are stable; this is not strictly true for the TE1 branch. Unstable NGW’s display a rich set of nonstationary phenomena, including soliton formation and nonlinear beating effects. Characteristic transformation lengths depend strongly on the definite, unstable initial NGW profile. The main effect of cladding losses is that the field tries to avoid the lossy region, leading to a considerable loss reduction. This property may destroy characteristic NGW features for propagation lengths approaching the absorption length of the lossy cladding. Phase-locked single-soliton and multisoliton emission can be induced by launching linear guided modes with the appropriate power flow through one of the film end faces.

Characterization of rutile and anatase powders by thermal analysis

Abstract: Anatase and rutile powders prepared by various methods were characterized by thermoanalytical studies up to 1400 °C using a simultaneous TG-DTG-DTA apparatus. Preparation techniques were developed for the manufacture of amorphous titania, pure anatase, stabilized anatase and pure rutile.

Morphology of neurones associated with the antennal heart of Periplaneta americana (Blattodea, Insecta).

Abstract: Innervation of the antennal heart, an independent accessory circulatory motor in the head of insects, was investigated in the cockroach Periplaneta americana by use of axonal cobalt filling and transmission electron microscopy. The muscles associated with this organ are innervated by neurones located in a part of the suboesophageal ganglion, generally considered to be formed by the mandibular neuromere. Dorsal unpaired median (DUM) and paired contralateral neurones were stained. The axons of all these neurones run along the circumoesophageal connectives and through the paired nervus corporis cardiaci III into the corpora cardiaca. They pass through these organs forming fine arborizations there and exit anteriorly as a small pair of nerves which terminate at the antennal heart-dilator muscles. Numerous branches of these nerves extend beyond the lateral borders of the large transverse dilator muscle and terminate in the ampullar walls of the antennal heart. These neurosecretory fibres form neurohaemal areas which obviously release their products into the haemolymph, which is pumped into the antennae. The possible functions of the neurones associated with the antennal heart are discussed with respect to both, their role as a modulatory input for the circulatory motor and as a neurohormonal release site.

Investigation of quantitative SiOH determination by the silane treatment of disperse silica

Abstract: The concentration of free silanol groups after treatment of disperse silica with 3-(trimethoxysilyl) propyl methacrylate (A-174) was studied in substance pellets by IR spectroscopy. There are significant structural differences between the silica which was treated with gaseous silane and that which was treated in solution. By gas-phase silanation a monolayer of methacrylate was formed, while in solution a polylayer was formed. This conclusion results from a determination of carbon content by means of elemental analysis in addition to an IR spectroscopic determination of the SiOH concentration remaining in the silane-treated silica surface. Silylation by means of hexamethyldisilazane was found to be a convenient method to determine the concentration of these residual silanol groups.

Critical steps in degradation of chloroaromatics by rhodococci I. Initial enzyme reactions involved in catabolism of aniline, phenol and benzoate by Rhodococcus sp. An 117 and An 213

Abstract: Two bacterial isolates (i.e. strains An 117 and An 213) capable of growing with aniline, phenol as well as benzoate as the sole carbon and energy source were studied with respect to (i) their taxonomic position, (ii) the enzyme reactions which initiate catabolism of the respective aromatic compounds, and (iii) the general type of regulation of the respective enzymes. Both isolates were established to be representatives of the actinomycete-genus Rhodococcus. Experiments with resting cells and cell-free extracts, respectively, revealed that in the two strains under study catabolism of each of the unsubstituted aromatic compounds occurs via the β-ketoadipate pathway (with catechol as the central metabolite) due to the action of inducible enzymes. Although being potent inducers of the ring-cleaving catechol 1,2-dioxygenase in strains An 117 and An 213, all of the monochlorinated derivatives of aniline, phenol and benzoate, respectively, failed to support cell growth of the organisms. Cis, cis-muconic acid proved to be non-metabolizable by resting An 117 and An 213 cells, although substantial (inducible) muconate cycloisomerase activity was detectable in crude extracts prepared from the respective cell preparations. NADPH-depending phenol hydroxylase activity could be demonstrated in crude extracts from phenol-grown An 117 and An 213 cells. Evidence is presented that in both Rhodococcus strains under study substantial de novo synthesis of at least the initial aromatics-oxygenating enzymes can be induced by phenol and aniline, respectively, even in the presence of either succinate (An 117) or acetate (An 213) which are known to be ortho-pathway catabolites.

Theory of Infrared Transmission Spectra of Thin Insulating Films

Abstract: It will be demonstrated that the so-called LO–TO splittings in the infrared spectra of thin amorphous insulating layers are a consequence of boundary conditions. Es wird gezeigt, das die sogenannten LO–TO-Aufspaltungen in IR-Spektren dunner amorpher Isolatorschichten aus Randbedingungen folgen.

Surface smoothing and roughening by dielectric thin film deposition.

Abstract: Recently we suggested a simple model that described the modification of the surface roughness profile ξ(r) of a sub­ strate after deposition of a thin dielectric layer. With the help of this model the behavior of the total integrated backscattering experimentally observed could be explained satis­ factorily. Having considered film growth-induced surface smoothing as well as additive film roughness we assumed the isotropic film surface profile ξ2(r) to be a superimposition of two statistically independent contributions:

Synthese von aromatischen Polyketonen durch Fällungspolykondensation

Abstract: Aromatische Polyketone wurden durch Fallungspolykondensation aus den Saurechloriden der Iso- und Terephthalsaure, des 3,3-Bis(4′-carboxy-phenyl)phthalids, des Bis(4-carboxy-phenyl)ethers jeweils mit Diphenylether sowie direkt aus 4-Phenoxybenzoylchlorid hergestellt Der Einiflus von Katalysator, Losungsmittel und Temperatur auf den Syntheseverlauf wurde untersucht und die Struktur der erhaltenen Polyketone aufgeklart Aromatic Polyketone are synthesized by reaction of the acyl chlorides of iso- and terephtlialic acid, 3,3-bis(4′-carb-oxyphenyl)phthalide, bis(4-carboxy-phenyl)oxide with diphenyloxide and by reaction of 4-phenoxy-benzoylchloride under the conditions of precipitation polycondensation The influence of catalyst, solvent and temperature on the polymer synthesis is studied The structures of the resulting polyketones are estimated

The cerium perhydroxide-diaminobenzidine (Ce-H2O2-DAB) procedure. New methods for light microscopic phosphatase histochemistry and immunohistochemistry.

Abstract: New light microscopic visualization methods were developed for the histochemical detection of non-specific alkaline and acid phosphatase, Mg-, Ca- and Na, K-dependent adenosine triphosphatase, myosin adenosine triphosphatase, glucose-6-phosphatase, 5'-nucleotidase and thiamine pyrophosphatase with cerium ions as trapping agents in cryostat and plastic sections. The techniques are based on the conversion of cerium phosphate into cerium perhydroxide by H2O2 which decomposes at 55 degrees-60 degrees C into cerium hydroxide and oxygen radicals. These radicals are able to oxidize diaminobenzidine (DAB) to DAB brown. Addition of nickel ions to the DAB-H2O2 mixture generates bluish-black stained nickel-DAB complexes. Compared with the classical metal precipitation, azo, azoindoxyl and tetrazolium procedures the H2O2-DAB and especially the H2O2-DAB-nickel methods provided identical or superior results in catalytic phosphatase histochemistry and immunohistochemistry when using non-specific alkaline phosphatase as the enzyme label.

Self phase modulation in a femtosecond pulse amplifier with subsequent compression

Abstract: The pulses from a colliding-pulse mode-locked dye laser (100 fs, 20 pJ) are amplified to 0.2 mJ and self phase modulated in an excimer laser pumped dye amplifier. Suitable chirp compensation leads to nearly bandwidth-limited pulses of about 50 fs duration.

The action of tentoxin on membrane processes in plants

Abstract: Tentoxin, a fungal phytotoxin, with its complex mode of action on plant membrane processes, is currently the best known example of a phytotoxic substance, with the literature going back more than 20 years and including a number of conflicting reports, which have not yet been adequately reconciled. This minireview covers all effects of tentoxin obtained at different levels of organization in several plant species (chloroplast structure and function, stomatal movements and guard cell protoplasts, leaf and root plasmalemma, ion uptake and translocation and internal ion concentrations) and suggests a number of targets for tentoxin which merit investigation. Besides the demonstration of the complexity of phytotoxin action and its possible relationship with other signal exchange mechanisms operating between microorganisms and plants, tentoxin may also provide a valuable tool for obtaining further information about the regulation of ion transport in plants.

Mechanical emergency stimulation in asystole and extreme bradycardia

Abstract: Repetitive precordial thumping is the simplest method of temporary cardiac pacing. In 90 patients out of 100 with witnessed cardiac arrest because of asystole or marked bradycardia the critical situation could be effectively bridged over by this until a sufficient spontaneous rhythm returned or electrostimulation was ready to function. 69 patients were conscious during the stimulation. During the mechanical pacing only in 2 patients there occurred ventricular flutter or fibrillation, which was stopped by electric defibrillation. The existence of the myocardial contractility is the presupposition for effective mechanical and electrical pacing.

Hormonal control of postnatal development of renal tubular transport of weak organic acids.

Abstract: We have postulated that the maturation of the renal transport mechanism for weak organic acids is controlled by thyroid and adrenal hormones Administration of T3 and T4 (20 μg/100 g body wt for 3 days) to immature rats enhanced by ∼50% the accumulation of p-aminohippurate (PAH) in renal cortical slices of 5- to 30-day-old rats The effect of T3 was lower, while T4 had no effect, in 50- and 105-day-old animals Enhancement of PAH transport became apparent 24 h and disappeared by 9 days after the end of hormone treatment Administration of a booster dose of T3 (1 μg/100 g body wt) on day 9 brought the level of PAH accumulation to values similar to those observed 24 h after the end of the initial 3 days of T3 administration Dexamethasone administration (80 mg/100 g body wt for 3 days) affected PAH uptake only in cortical slices obtained from 5-day-old rats Changes in PAH accumulation did not correlate with changes in kidney weight or protein synthesis, indicating that they were mediated by the hormones rather than being consquent to growth

Personality and quantified neuromuscular activity of the masticatory system in patients with temporomandibular joint dysfunction.

Abstract: Patients suffering from temporomandibular joint dysfunction syndrome (TMJS) and healthy volunteers were examined by means of MMPI questionnaire and electromyography (masseter, anterior temporal and anterior digastric muscles) at rest and during natural chewing. In response to mental load (arithmetic chain task) TMJS patients showed an increase in postural activity and partly rhythmical short augmentations above the mean level of this activity. Chewing potentials were considerably diminished in patients compared with controls. There was evidence for neurotic disorders in the patients MMPI (neurotic triad: higher scores on hypochondria, depression, hysteria). Significant differences (multivariate variance and discriminant analysis: P less than 0.001) between patients and controls were found both in the group with psychic signs (MMPI scales) and in the group of quantitative electromyographic parameters. However, a sufficient discrimination was only obtained by a combination of both parameter groups. The results show that probably psychic dynamics, as well as the structure of neuromuscular activity within the masticatory system, are important in the aetiopathogenesis of TMJS.

Cellular heterogeneity. Explanation for changing of tumor phenotype and biologic behavior in soft tissue sarcomas.

Abstract: Many human soft tissue sarcomas are known to show variable structures in a given tumor and to be able of changing the histological feature during the course of the disease. These facts prompted an experimental study in order to ascertain if by use of long-term cultures of an established rat fibrosarcoma cell line (RFS) in respective inoculation tumors a histological picture different from the original fibrosarcoma could be produced. It was found that inoculation tumors generated by later subcultures partly corresponded to tumors with features of malignant histiocytomas and malignant fibrous histiocytomas. In a further experiment we attempted to initiate metastatic dissemination of a primarily non-metastasizing xenotransplanted RFS sarcoma in nude mice. By repeated diminution operations comparable to inadequate tumor surgery in human metastasis formation in lung parenchyme was attained. Taking into account cellular heterogeneity as basically responsible for the phenomena observed, different causal aspects concerning the experimental results are discussed. We deduce from our findings that the concept of histogenetic classification of soft tissue sarcomas should be replaced by an interpretation according to the actual differentiation. This also applies to malignant fibrous histiocytomas which are at least in part mesenchymal tumors and not descendants of mononuclear phagocytic cells and may originate by a dedifferentiation process of otherwise defined sarcoma types.

Critical steps in degradation of chloroaromatics by rhodococci II. Whole‐cell turnover of different monochloroaromatic non‐growth substrates by Rhodococcus sp. An 117 and An 213 in the absence/presence of glucose

Abstract: Kinetic experiments were performed to examine the effect of glucose and some related compounds on the removal of different monochloroaromatic non-growth substrates (i.e. monochloroisomers of aniline, phenol and benzoate, respectively) by resting pre-adapted cells of either Rhodococcus sp. An 117 or Rhodococcus sp. An 213. With both strains, the use of glucose as the additional carbon substrate allowed to differentiate between “cometabolizable” monochloroaromatics (i.e. 2-chloroaniline, 3-chloroaniline, 3-chlorophenol, 4-chlorophenol whose turnover appeared to be primarily limited by the availability of reducing power and/or energy to the cells) and those which were weakly removed “under any condition” due to narrow substrate specificity of the enzymes initiating the transformation process. In a second line of investigation, the reduction of ferricyanide by resting An 117 or An 213 cells was shown to exhibit a pattern of cosubstrate-dependence analogous to that found for turnover of the “cometabolizable” monochloroaromatics. As demonstrated with different cell preparations of strain An 117, whole-cell ferricyanide reduction strongly interferred with the cometabolic turnover of various monochloroaromatic non-growth substrates. The results obtained are those to be expected if the former (NAD(P)H-dependent) type of process, in preference to the second one, would consume the reducing equivalents which become available from the metabolism of glucose. They point out the opportunity to make use of the carbon substrate-dependent whole-cell reduction of ferricyanide (or of other external electron acceptors) as a rapid and inexpensive assay of pre-screening for carbon compounds which would function as energy-replenishing cosubstrates in the (cometabolic) turnover of xenobiotic non-growth substrates by rhodococci.